Preheat oven to 375F (190C).

Wash potatoes and poke holes with a fork.

Bake potatoes for 45 minutes (adjust time for size) until easily pierced with a skewer.

Remove from oven and let cool slightly.

Peel the potatoes and slice into 1/2 inch slices.

Melt butter or olive oil in a saucepan over low heat.

Stir in flour and cook for 7 minutes, stirring constantly, without browning.

Remove pan from heat and whisk in milk quickly until smooth.

Return to stove and cook over medium heat for 18-20 minutes, stirring until thickened to cream consistency.

Add 80% of the cheddar cheese and stir until smooth.

Add cooked potato slices, salt, and pepper, and fold together.

Pour into a casserole dish.

Sprinkle the remaining 20% of cheese over the top.

Dust with paprika.

Bake in 375F oven for 30 minutes, or until golden brown and bubbly.